--- drivers/gpu/drm/linux_fb.c.orig	2022-05-31 08:17:34 UTC
+++ drivers/gpu/drm/linux_fb.c
@@ -222,6 +222,33 @@ __register_framebuffer(struct linux_fb_info *fb_info)
 	fb_info->fbio.fb_fbd_dev = device_add_child(fb_info->fb_bsddev, "fbd",
 				device_get_unit(fb_info->fb_bsddev));
 
+/* This block should be removed after /sys/sys/fbio.h has been updated. */
+#ifndef FB_FLAG_ROTATE_MASK	/* Transitional, from /sys/sys/fbio.h */
+#define FB_FLAG_ROTATE_0	    0x00	/* rotate fb 0 degrees clockwise */
+#define FB_FLAG_ROTATE_90	    0x08	/* rotate fb 90 degrees clockwise */
+#define FB_FLAG_ROTATE_180	    0x10	/* rotate fb 180 degrees clockwise */
+#define FB_FLAG_ROTATE_270	    (FB_FLAG_ROTATE_90 | FB_FLAG_ROTATE_180)
+#define FB_FLAG_ROTATE_MASK	    0x18
+#define FB_FLAG_ROTATE_NODEFAULT    0x20	/* do not load console defaults */
+#endif
+
+	/* Pass the FB_ROTATE hints to FreeBSD's vt(4) fb_flags. */
+	fb_info->fbio.fb_flags &= ~FB_FLAG_ROTATE_MASK;
+	switch (fb_info->fbcon_rotate_hint) {
+	case FB_ROTATE_UR:
+	    fb_info->fbio.fb_flags |= FB_FLAG_ROTATE_0 | FB_FLAG_ROTATE_NODEFAULT;
+	    break;
+	case FB_ROTATE_CW:
+	    fb_info->fbio.fb_flags |= FB_FLAG_ROTATE_90 | FB_FLAG_ROTATE_NODEFAULT;
+	    break;
+	case FB_ROTATE_UD:
+	    fb_info->fbio.fb_flags |= FB_FLAG_ROTATE_180 | FB_FLAG_ROTATE_NODEFAULT;
+	    break;
+	case FB_ROTATE_CCW:
+	    fb_info->fbio.fb_flags |= FB_FLAG_ROTATE_270 | FB_FLAG_ROTATE_NODEFAULT;
+	    break;
+	}
+
 	/* tell vt_fb to initialize color map */
 	fb_info->fbio.fb_cmsize = 0;
 	if (fb_info->fbio.fb_bpp == 0) {
@@ -281,7 +308,9 @@ linux_unregister_framebuffer(struct linux_fb_info *fb_
 int
 linux_fb_get_options(const char *connector_name, char **option)
 {
+	int rotation;
 	char tunable[64];
+	char (*optbuf)[sizeof(",rotate=360")];
 
 	/*
 	 * A user may use loader tunables to set a specific mode for the
@@ -295,6 +324,11 @@ linux_fb_get_options(const char *connector_name, char 
 	 * Example of a mode applied to all connectors not having a
 	 * connector-specific mode:
 	 *     kern.vt.fb.default_mode="640x480"
+	 *
+	 * Example of a mode option applied to all connectors not having a
+	 * connector-specific mode, where the angle is the number of degrees
+	 * counter-clockwise to rotate the display:
+	 *     kern.vt.fb.default_mode=",rotate=270"
 	 */
 	snprintf(tunable, sizeof(tunable), "kern.vt.fb.modes.%s",
 	    connector_name);
@@ -302,10 +336,26 @@ linux_fb_get_options(const char *connector_name, char 
 		printf("[drm] Connector %s: get mode from tunables:\n", connector_name);
 		printf("[drm]  - %s\n", tunable);
 		printf("[drm]  - kern.vt.fb.default_mode\n");
+		printf("[drm]  - screen.rotate\n");
 	}
 	*option = kern_getenv(tunable);
 	if (*option == NULL)
 		*option = kern_getenv("kern.vt.fb.default_mode");
+	if (*option == NULL) {
+		if (getenv_int("screen.rotate", &rotation) != 0) {
+			switch (rotation) {
+			case 90:
+			case 270:
+				rotation = (rotation + 180) % 360;
+			case 180:
+				optbuf = malloc(sizeof(*optbuf), DRM_MEM_DRIVER,
+				    M_WAITOK | M_ZERO);
+				snprintf(*optbuf, sizeof(*optbuf), ",rotate=%d",
+				    rotation);
+				*option = *optbuf;
+			}
+		}
+	}
 
 	return (*option != NULL ? 0 : -ENOENT);
 }